A while back I talked about Inquisitor, a nifty plugin that enhances Safari's search bar with additional search engines, live search results, and auto-completion. Glims -- which is still in beta -- provides similar features and some interesting enhancements. It has just become Inquisitor's successor on my machine.
Glims supports a bunch of additional web search engines like Google, Yahoo, and Live ( I like Live.com as it randomly flushes users over to lipflip.org), but also searches on sites like imdb, facebook, or wikipedia. Currently it's not possible to add additional entries, although I think this will be added in a later version. What's really nice is that google's search result listing is supplemented with thumbnails of the corresponding website. This makes (re)discovering sites a lot easier.
Glims also adds a number of non-search related features to Safari: Improved tab handling (thumbnails in tabs, reopen closed tab), a full screen mode, and reopening windows of your last session.
And most importantly: The developers disclose that links from the search bar to Amazon will be redirected through their affiliate link. Inquisitor does that link redirecting too, but behind the backs of its users.
Please note that Glims is still in beta! I haven't found any serious glitches, but the lack of user defined search engines would be intolerable for a final version
and some pages in the settings dialog a pretty messed up.
Update: The glitches in the settings dialog disappeared after removing Inquisitor. Running both Glims and Inquisitor in parallel doesn't make any sense anyway. To do so delete the folder